Experiment 4 acceptability fixed effects.

We present four experiments investigating adaptation to a regional grammatical structure through reading exposure, using both the needs + past participle construction (e.g., The car needs washed) and the double modal construction (e.g. You might could go there). In each experiment, participants read two stories containing informal dialogue. Half of the participants were exposed to one of the regional constructions and half were not. Those readers exposed to the regional constructions adapted, gradually reading the novel constructions faster over 9 to 15 exemplars. The degree to which the exposed group learned the construction was tested in two ways. In the first two experiments, learning was measured by comparing reading times to acceptable and unacceptable variants of the novel constructions. Readers did not learn either the verb tense rule for the needs construction (Experiment 1) or a simple ordering rule for double modal constructions (Experiment 2). Similarly, in Experiments 3 and 4, metalinguistic judgments used to test learning revealed that participants had failed to acquire the regional grammar of either novel construction. These experiments suggest that the adaptation effects reflect learning some general properties of the experimental stimuli, not learning the syntactic constructions themselves.本研究开展四项实验，旨在探究通过阅读接触实现区域语法结构适应性学习的机制，实验同时采用了两种目标构式：needs+过去分词构式（needs + past participle construction，例如The car needs washed）与双重情态动词构式（double modal construction，例如You might could go there）。每项实验中，被试均阅读两篇包含非正式对话的故事，其中半数被试会接触某一种区域构式，另一半被试则无此类接触。接触过区域构式的被试出现了适应性变化：在9至15个语例的阅读过程中，他们对新型构式的阅读速度逐步提升。研究通过两种方式评估接触组对该构式的掌握程度。在前两项实验中，学习效果通过对比被试阅读新型构式的合格变体与不合格变体的阅读时长来衡量；结果显示，被试既未掌握needs+过去分词构式的动词时态规则（实验1），也未习得双重情态动词构式的简单语序规则（实验2）。与之类似，在实验3与实验4中，用于测试学习效果的元语言判断（metalinguistic judgments）任务结果显示，被试均未掌握任一新型构式的区域语法规则。上述实验结果表明，此类适应性变化反映的是被试对实验刺激的部分通用属性的学习，而非对句法构式本身的习得。